docs: def save_performance(db, job_id, records):
      """
      Save in the database the performance information about the given job.
  
      :param db: a :class:`openquake.server.dbapi.Db` instance
      :param job_id: a job ID
      :param records: a list of performance records
      """
      # NB: rec['counts'] is a numpy.uint64 which is not automatically converted
      # into an int in Ubuntu 12.04, so we convert it manually below
      rows = [(job_id, rec['operation'], rec['time_sec'], rec['memory_mb'],
               int(rec['counts'])) for rec in records]
      db.insert('performance',
                'job_id operation time_sec memory_mb counts'.split(), rows)